LDAP connection comparison - Microsoft Platform Application vs Third Party Application

Hi guys,

I'm having a issue related to failover among Domain Controllers. I have DC site and DR site. When Domain Controller in DC site is turned off:

Microsoft Platform Application switch to Domain controller in DR site automatic & logon normally.

Third Party Application maybe not switch to DR & logon failed.

Can anyone explain for me "Failover LDAP" between MS Platform App vs Third Party App that which different?

Thanks so much